Hello Cristy, If you're AFAA certified...you will find an "Agreement and Release of Liability" form in your AFAA book (first edition, 2006, revised 2007) in the Appendix C...page 429.
Hope this Helps!
Sincerely,
Michael

I agree with Shawn. It's always a good idea to have an attorney look over any template form that you are considering using so that your particular circumstances can be taken into account. Having a template form to go over is a great way to short-circuit the time you spend with the attorney and his or her time since their not having to draft a form from scratch though. Good luck.